> Ignoring status codes My favorite is when everything returns a 200, but the response is something like: { status: "fail", error: "forbidden" } Sometimes they even include the 403 in the response, almost like the developer is giving you a giant middle finger.
I remember reading that ISP's and browsers can do interesting things to non-2xx responses. In that case applications do not even have a chance to handle the error. IIRC Facebook's API does this because they encountered problems with mobile browsers deciding to do weird things with non-2xx responses.
You may be thinking about DNS hijacking by ISPS, but not non-200 issues. There are bound to be some terrible apps out there that respond badly as well, but that's really no excuse.